The entire disclosure of Japanese Patent Application No. 2000-189213 filed on Jun. 23, 2000, including the specification, claims, drawings, and summary is incorporated herein by reference in its entirety.
1. Field of the Invention
The present invention relates to a printing press, which can drive an ink supply apparatus solely by oscillation of a drive motor, for example.
2. Description of the Related Art
An ink supply apparatus of a printing press for supplying ink to the surface of a plate attached to a plate cylinder comprises an ink fountain for storing ink, and a group of rollers for transferring ink from the ink fountain while uniformly distributing the ink in respective directions. The ink transferred to the end portion of the group of rollers is supplied to the plate cylinder via an ink form roller.
In general, such an ink supply apparatus (hereinafter referred to as an xe2x80x9cinkerxe2x80x9d) for effecting ink supply operation employs a drive system such that the ink supply apparatus is mechanically connected to a driving side (main unit) which includes a plate cylinder and which rotates the plate cylinder, to thereby receive rotational torque from the driving side.
Further, for a short-time operation such as an operation for a printing preparation, maintenance, or cleaning of the inker, there has been developed a system for breaking the mechanical connection between the inker and the driving side by means of a clutch and for rotating the inker independently of the main unit by means of a separate drive source (motor) (Japanese Patent Application Laid-Open (kokai) No. 63-315244).
Meanwhile, when rainbow printing is to be performed for preventing forgery, an oscillation apparatus is built into the inker in order to adjust oscillation conditions of an oscillating roller.
A known oscillation apparatus is of a hydraulic-control-type in which ink stored in the ink fountain is supplied to the oscillating roller, and the oscillating roller is reciprocated along an axial direction thereof by means of a hydraulic cylinder, whereby the ink is supplied to the plate cylinder while being spread in the axial direction of the oscillating roller (see, for example, Japanese Patent Application Laid-Open (kokai) No. 63-264352 and Japanese Utility Model Application Laid-Open (kokai) No. 63-170138).
In the above-described hydraulic-control-type oscillation apparatus, a mechanism for controlling the hydraulic cylinder is complicated; and oscillation width and the number of times of oscillations are difficult to adjust finely.
In view of the foregoing, a two-motor-type oscillation apparatus may be employed, which uses a motor for the oscillation drive and a motor for the oscillation width adjustment instead of the above-described hydraulic cylinder. However, in such a case, it becomes necessary to install two motors having the same specifications for each inking unit for a single color.
However, in the case where a separate drive source is provided in order to improve maintainability or the like as described above, three drive sources are needed in total for each inking unit for a single color.
In view of the foregoing, an object of the present invention is to provide a printing press, which can drive an inker solely by use of a motor for oscillating an oscillating roller.
Another object of the present invention is to reduce the number of motors to be installed, thereby reducing cost and saving space.
In order to achieve these objects, the present invention provides a printing press, comprising a first rotary member; a first motor for rotating the first rotary member; a second rotary member rotated by the first motor and movably supported in an axial direction thereof; a second motor for moving the second rotary member in the axial direction and for rotating the second rotary member; connecting/disconnecting means for selectively permitting and stopping transmission of rotation from the first motor to the second rotary member; and a clutch for stopping transmission of rotation from the second motor to the second rotary member when the first motor is connected to the second rotary member by the connecting/disconnecting means such that the first motor can rotate the second rotary member and for connecting the second motor with the second rotary member such that the second motor can rotate the second rotary member when transmission of rotation from the first motor to the second rotary member is stopped by the connecting/disconnecting means.
The connecting/disconnecting means may be frame moving means for separating a first frame supporting the first rotary member and a second frame supporting the second rotary member from each other, to thereby stop transmission of rotation from the first motor to the second rotary member.
Alternatively, the connecting/disconnecting means may be a second clutch provided between the first rotary member side and the second rotary member side and adapted to stop transmission of rotation from the first motor to the second rotary member.
The first rotary member may be a cylinder or an oscillating roller of an offset printing press.
Preferably, the printing press further comprises a sensor for detecting a state in which the first frame and the second frame are in proximity to each other, wherein the clutch is prevented from entering a connected state when the sensor detects the state in which the first frame and the second frame are in proximity to each other.
Preferably, the printing press further comprises an oscillation mechanism for converting rotation transmitted from the second motor to reciprocating motion of the second rotary member; an oscillation-width adjustment mechanism for adjusting an oscillation width of the second rotary member; and oscillation-width adjustment means for operating the oscillation-width adjustment mechanism.
Preferably, the oscillation mechanism includes a swing member which swings upon operation of the second motor, a moving member movably supported on the swing member, and an engagement member rotatably supported on the moving member and being in engagement with the second rotary member, and wherein the oscillation-width adjustment mechanism is configured such that, upon operation of the oscillation-width adjustment means, the oscillation-width adjustment mechanism moves the moving member to thereby adjust a distance between a swing center of the swing member and a rotation center of the engagement member. Preferably, the moving member is slidably supported on the swing member.
Preferably, the oscillation mechanism includes a crank mechanism whose input side is connected to the second motor, a swingably-supported swing lever whose base end side is connected to the output side of the crank mechanism, a slide lever slidably supported by the swing lever such that the distal end side of the slide lever can move toward and away from a swing center of the swing lever, a first link plate whose one end side is rotatably supported by the distal end side of the slide lever, a swingably-supported swing plate, the other end side of the first link plate being rotatably connected to the base end side of the swing plate, and a cam follower provided at the distal end side of the swing plate and inserted into a groove wheel of the second rotary member; and the oscillation-width adjustment mechanism includes a worm gear connected to the oscillation-width adjustment means, a worm wheel in meshing engagement with the worm gear, a transmission shaft coaxially connected to the worm wheel, a second link plate whose one end side is connected to the transmission shaft, and the slide lever whose base end side is rotatably connected to the other end side of the second link plate.